As a medical device for applying a medical treatment to a local part in a living body, conventionally, there has been known a medical treatment device wherein an infusion needle is disposed in a lumen of a catheter so as to be able to move forward and backward, the catheter is inserted into the local part or the vicinity thereof, and a drug solution is infused from a distal portion of the infusion needle into the local part.
For instance, Patent Document 1 discloses a drug solution infusing medical treatment device wherein a drug solution is infused by projecting an infusion needle to a lateral side of a catheter inserted in a blood vessel. In this medical treatment device, the catheter is inserted in the blood vessel, and a pair of balloons disposed at a predetermined interval along a forward-backward direction is both inflated, whereby a sealed region closed at both ends thereof is formed in the blood vessel. After forcibly draining blood from the sealed region, the infusion needle is projected out via an opening formed in a catheter side wall between the pair of balloons to puncture a blood vessel wall, and, in this state, the drug solution is infused via a distal portion of the infusion needle.
An inside portion of a lumen of the catheter on the forward side of the opening through which to project the infusion needle is closed with a core member formed at a rear end thereof with a curved-surface guide part inclined with respect to an axial direction of the catheter, and the curved-surface guide part is disposed adjacent to the opening in the catheter side wall. Therefore, when a drug solution infusion tubing formed at a distal end thereof with the infusion needle is moved forward along the lumen of the catheter, the distal portion of the infusion needle makes contact with the curved-surface guide part and, further, is guided by the curved-surface guide part, to be projected via the opening in the catheter side wall to the outside of the catheter.